| Co-Investigator(Kenkyū-buntansha) |
HOSODA Kiminori Kyoto Univsity, Environmetal Study, Assistant Prof., 人間環境学研究科, 助手 (40271598)
YOSHIMASA Yasunao Kyoto Univsity, Clinical Science and Medicine, Lecturer, 医学研究科, 講師 (00252437)
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| Research Abstract |
(1) Effect of thiazolidinediones on leptin production and insulin action in rat adipocytes. Thiazolidinedione, an insulin sensitizer, reduced protein and mRNA levels of leptin in rat adipocytes after 24 hours. This compound also increased 2-deoxyglucose uptake in the adipocytes. However, mRNA level of leptin and insulin action were not changed, when the adipocytes were incubated with exogenous leptin for 24 hours, Thus it is suggested that exogenous leptin dose not affect the primary culture of adipocytes directly.
(2) Effect of leptin on insulin action in culture of skeletal muscle Leptin did not affect the insulin action including insulinsignaling systems and glucose uptake in culture of skeletal muscles (L6 cells).
(3) Insulin action in leptin transgenic mouse Leptin transgenic mouse showed no accumulation of adipocytes, both white and brown adipocytes. In vivo insulin action determined by intraperitoneal glucose tolerance test (GTT) and insulin tolerance test (ITT) showed enhanced insulin sensitivity in the transgenic mice. It is suggested that leptin has lipoatrophic effect on adipocytes and insulin action, and that insulin action is enhanced Through central nervous systems by leptin.
(4) Concentration of plasma leptin in human There were correlations between plasma leptin and % fat , body mass index significantly. And the was also gender difference in leptin concentration (male<female). However aging did not affect the concentration. We also found some polymorphisms in leptin gene, but there were no relation between leptin and the polymorphisms in Japanese obese subjects.
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